Pneumatic wheel-tire.



No. 636,896. Patented Nov. 14, I899. G. H. CLARK.

PNEUMATIC WHEEL TIRE.

(Application filed may 24, 1899.)

(No Model.)

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WATENT GEORGE H. CLARK, OF BOSTON, MASSACHUSETTS.

PNEUMATIC WHEEL-*TIRE.

SPECIFICATION forming part of Letters Batent No. 636,896, dated November14, 1899,

Application filed May 24., 1899. Serial No. 718,044. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE H. CLARK, of Boston, county of Suffolk, andState of Massachusetts, have invented an Improvement in PneumaticWheel-Tires, of Whichthe fol lowing description, in connection with theaccompanying drawings, is a specification, like letters on the drawingsrepresenting like parts.

This invention relates to pneumatic wheeltires, and has for its objectto produce a tire having a non-puncturable tread which shall be lightand very resilient and which may be securely attached to the contiguousparts of the tire by vulcanization.

In accordance with this invention the tire consists, essentially, of anair-tube inclosed within a wrapper of expansible materialsuch, forinstance, as a strip of canvas cut on the bias, a non-extensible stripsecured to the tread side of said inclosed air-tube, and

a resilient protecting-strip secured to thev outer or tread side of saidnon-extensible strip, which is composed, essentially, of granulated,ground, or powdered cork and rubber, said materials being formed intosubstantially a homogeneous mass and in the proportions of about halfand half, and an outer covering which may be and preferably is composedof an inner canvas layer and an outer rubber layer. All of the aforesaidparts will be vulcanized together, and as the resilient protectingtread-strip contains a large percentage of rubber it will readilyvulcanize to the contiguous parts of the tire and be thereby firmlysecured in place from end to end and from side to side.

I find in practice that a tread-strip composed of rubber and granulated,ground, or powdered cork produces a very resilient tread-strip, whichnot only gives the tire the required resiliency, but also effectuallyprotects the air-tube from punctures, and, furthermore, such atread-strip may be firmly secured in place by uniting at all parts withthe contiguous parts of the tire during the process of vulcanization.

The drawing shows in cross-section a pneumatic wheel-tire embodying thisinvention.

a represents the air-tube, which is of any usual or suitableconstruction. I) is a canvas or other wrapper thereon which completelyincl'oses it, and said wrapper is made expansible to a certainextent--as, for instance, it may be made by cutting the cam vas on thebias. 0- represents a non-exten sible strip which may be also composedof canvas or other suitable material, and said strip is placed upon theouter or tread side of the inclosed air-tube.

(1 represents the resilient protecting-strip, which is composed ofgranulated, ground, or powdered cork and rubber made into sub stantiallya homogeneous mass in the propor= tions of about half and half, althoughI prefer to add a small percentage of vegetable pitch in some instances.These relative pro portions, however, may be varied more or less. Theresilient protecting-strip e is se cured to the outer or tread side ofthe nonextensible strip a. An outer covering is then applied, which isherein shown as composed 'of an inner layer of canvas or other suitablematerial 6 and an outer layer of rubber e,although any usual or suitableouter covering may be employed in lieu of that herein shown.

The layers or wrappers of canvas may be coated with rubber or withrubber-cement, if desired, to enhance their tendency to adhere to thecontiguous parts during the manufacture of the tire.

The tire thus constructed is vulcanized and all of the aforesaid partsfirmly secured to gether by such process.

Prior to this invention many forms of tread strips have been made, but,so far as I am aware, no tread-strip has ever been made composed,essentially, of granulated, ground, or powdered cork and rubber, wherebya light, flexible, and very resilient tread-strip is produced and onethat can be firmly secured in place by vulcanization.

I claim-- In a pneumatic wheel-tire, an air-tube, an expansible wrapperinclosing it, a non-extensible strip secured to the tread side of saidinclosed air-tube, a resilient protecting-strip secured to the outerside of said non-extensible strip composed essentially of granulated,ground or powdered cork and rubber, and an outer covering for theaforesaid parts, all of said parts being vulcanized together,substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

GEORGE H. CLARK.

Witnesses:

B. J. Novas, JENNIE L. HUTCHINSON.

